1. Sift the flour, ginger, bicarbonate of soda and salt into a bowl and stir in the sugar. Put the butter and treacle in a saucepan and heat gently until the butter is melted, remove from the heat and leave to cool for 15 minutes.
2. Beat the cooled butter mixture into the dry ingredients with the milk and egg and mix together until evenly combined, then knead briefly until smooth.
3. Take 15 g (1/2 oz) pieces of dough and roll them into balls. Flatten them into 5 cm (2 inch) discs and place them, slightly apart, on 2 large, lightly oiled baking sheets.
4. Sprinkle the biscuits with a little granulated sugar and bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 13-15 minutes until evenly browned. Leave to cool on the baking sheets for 2 minutes then transfer to a wire rack to cool. Repeat with the remaining dough to make 40-44 biscuits.